Switching power converters are widely used in a variety of applications and power levels because of their high efficiency and small amount of area/volume consumed. Widely accepted switching power converters include buck, boost, buck-boost, forward, flyback, half-bridge, full-bridge, and SEPIC topologies. Multiphase buck converters are particularly well suited for providing high current at low voltages needed by high-performance integrated circuits such as microprocessors, graphics processors, and network processors. Buck converters are implemented with active components such as a pulse width modulation (PWM) controller IC (integrated circuit), driver circuitry, one or more phases including power MOSFETs (metal-oxide-semiconductor field-effect transistors), and passive components such as inductors, transformers or coupled inductors, capacitors, and resistors. Multiple phases can be connected in parallel to meet high output current requirements.
The large number of components included in switching power converters and the typically high output current and power of such systems make it desirable to detect any component or connection failures in order to verify the full functionality of these systems and ensure that the switching power converters operates properly over its entire operating range. Voltage, current, power and temperature monitoring are commonly implemented to ensure proper operation under varying, unpredictable and unforeseen operating conditions. High-performance integrated circuits such as microprocessors, graphics processors, and network processors require several protection mechanisms to guard against voltage and current variations. Phase fault detection (PFD) is one protection mechanism that protects the load and also provides an effective diagnostic guidance for the user. An efficient, reliable and low-cost PFD scheme is highly desirable.